U.S. patent application number 13/659920 was filed with the patent office on 2014-05-01 for downhole sensor and method of coupling same to a borehole wall.
This patent application is currently assigned to SCHLUMBERGER TECHNOLOGY CORPORATION. The applicant listed for this patent is SCHLUMBERGER TECHNOLOGY CORPORATION. Invention is credited to Peter Airey, Hugues Dupont.
Application Number | 20140116726 13/659920 |
Document ID | / |
Family ID | 50544105 |
Filed Date | 2014-05-01 |
United States Patent
Application |
20140116726 |
Kind Code |
A1 |
Airey; Peter ; et
al. |
May 1, 2014 |
Downhole Sensor and Method of Coupling Same to A Borehole Wall
Abstract
Devices and methods for borehole seismic investigation are
provided. The devices are a downhole tool having gripping devices
which may improve contact between the downhole tool and the
borehole wall (or casing of the borehole wall) and reduce slippage
as compared to downhole tools without the gripping devices. The
methods involve lowering a downhole tool having the gripping
devices into a borehole and applying force to cause the gripping
devices to penetrate or create an indentation in the borehole wall
(or casing of the borehole wall). The methods and devices may
improve the coupling between the downhole tool and surface to be
monitored and/or may enhance the frequency range due to higher
coupling frequency as compared to downhole tools without the
gripping devices.
Inventors: |
Airey; Peter; (Saint Germain
Laval, FR) ; Dupont; Hugues; (Setagaya-ku,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCHLUMBERGER TECHNOLOGY CORPORATION |
Sugar Land |
TX |
US |
|
|
Assignee: |
SCHLUMBERGER TECHNOLOGY
CORPORATION
Sugar Land
TX
|
Family ID: |
50544105 |
Appl. No.: |
13/659920 |
Filed: |
October 25, 2012 |
Current U.S.
Class: |
166/381 ;
166/113 |
Current CPC
Class: |
E21B 23/01 20130101;
G01V 1/42 20130101; E21B 47/01 20130101; E21B 47/00 20130101 |
Class at
Publication: |
166/381 ;
166/113 |
International
Class: |
E21B 47/00 20060101
E21B047/00 |
Claims
1. A downhole tool for monitoring seismic waves, comprising: a. a
housing comprising at least one gripping device adapted to puncture
or create an indentation in a borehole wall or casing of a borehole
wall, if the borehole wall is cased, when the at least one gripping
device contacts the borehole wall and sufficient force is applied
to the housing; and b. at least one sensor integral with the
housing.
2. A downhole tool according to claim 1, wherein the at least one
gripping device includes at least one protruding spike.
3. A downhole tool according to claim 1, wherein the at least one
gripping device is mounted to the housing.
4. A downhole tool according to claim 1, wherein the at least one
gripping device includes at least three gripping devices and the at
least three gripping devices are arranged in a non-linear pattern
on the housing.
5. A downhole tool according to claim 1, wherein the at least one
gripping device is three gripping devices which are arranged in a
triangular geometry about the housing.
6. A downhole tool according to claim 1, wherein the at least one
gripping device is made of a material that is harder than the
borehole wall or the casing of the borehole wall, if the borehole
wall is cased.
7. A downhole tool according to claim 6, wherein the material
comprises tungsten carbide.
8. A downhole tool according to claim 1, wherein the downhole tool
has a coupling frequency of at least 1000 Hz.
9. A downhole tool according to claim 1, wherein the at least one
sensor is mounted on or within the housing.
10. A method for coupling a sensor to a borehole wall, comprising:
a. lowering a downhole tool into a borehole, wherein the downhole
tool comprises a housing having at least one gripping device and at
least one sensor; b. contacting the at least one gripping device
with a borehole wall; and c. applying a sufficient force to the
downhole tool to cause the at least one gripping device to
penetrate or create an indentation in the borehole wall.
11. A method according to claim 10, wherein the borehole wall is
cased, and the penetration or indentation is in the casing of the
borehole wall.
12. A method according to claim 10, wherein the at least one
gripping device includes at least three protruding spikes mounted
to the downhole tool and arranged in a non-linear pattern, and
contacting comprises contacting each of the three protruding spikes
with the borehole wall, and applying comprises applying a
sufficient force to cause each of the three protruding spikes to
penetrate or create an indentation in the borehole wall.
13. A method according to claim 10, wherein the force is applied by
a clamping or locking mechanism.
14. A method according to claim 13, wherein the clamping or locking
mechanism is chosen from extendable mechanical arms, an inflatable
bladder, bow springs and combinations thereof.
15. A method according to claim 10, wherein the downhole tool is a
bare sensor, a shuttle or a drill string tubular.
16. A method according to claim 10, wherein the downhole tool is a
shuttle or a drill string tubular and the at least one sensor is
mounted on or within the shuttle or drill string tubular.
Description
FIELD
[0001] The present disclosure relates to the study of underground
formations and structures, for example as it relates to oil and gas
exploration. The present disclosure relates more specifically to
downhole sensors and methods of coupling sensors to borehole
walls.
BACKGROUND
[0002] Borehole seismic investigation is among the tools that oil
and gas professionals use to assist them in understanding formation
properties. The quality of information derived from seismic data is
related to the quality of the monitoring process, and in the case
of sensors this can depend on how well the sensors reproduce the
particle motion of the borehole wall. Specifically, monitoring of
acoustic events, whether natural as in the case of some
microseismic events, or induced, such as in the case of firing a
controlled source or hydraulic fracturing, may be achieved using
several sensors mounted in a common enclosure. The resulting sensor
package is brought into contact with the surface to be monitored.
However, the ability of a sensor package to reproduce the motion of
the surface can be limited by the coupling frequency, above which
the motion of the sensor package differs from that of the surface
being monitored.
SUMMARY
[0003] The present disclosure relates to devices and methods for
coupling sensors to borehole walls. In some embodiments, the
devices and methods result in improved coupling between the sensor
and the formation to be monitored as compared to conventional
devices and methods. In some embodiments, the devices and methods
enhance the frequency that can be monitored as compared to
conventional devices and methods. In some embodiments, the devices
and methods improve the coupling between the sensor and formation
and enhance the frequency that can be monitored as compared to
conventional devices and methods.
[0004] In some embodiments, the device is a downhole tool equipped
with at least one gripping device adapted to puncture, or create an
indentation in, a borehole wall (or casing of a borehole wall if
the borehole wall is cased) when the at least one gripping device
contacts the borehole wall and sufficient force is applied to the
downhole tool. The downhole tool can be a bare sensor, a shuttle
which at least one sensor is mounted on or within and which has a
housing carrying at least one gripping device, or a
measurement-while-drilling (or logging-while-drilling) tool which
at least one sensor is mounted on or within and which carries at
least one gripping device. In some embodiments, the gripping
devices are protruding spikes. In some embodiments, the gripping
devices (for example the protruding spikes) are three gripping
devices mounted in a triangular geometry relative to one another.
The gripping devices may be made of a material that is harder than
the borehole wall or casing, such as tungsten carbide. The sensors
may be any sensors that are desirably coupled to the borehole wall,
such as geophones or accelerometers. In some embodiments, the
devices have a coupling frequency of at least 1000 Hz.
[0005] In some embodiments, the methods involve: lowering a
downhole tool carrying at least one gripping device into a
borehole, where the downhole tool may be a bare sensor, a shuttle
including at least one sensor, or a measurement-while-drilling (or
logging-while-drilling) tool including at least one sensor;
contacting the at least one gripping device with the borehole wall
(or casing of the borehole wall if the borehole wall is cased); and
applying a sufficient force to the downhole tool to cause the at
least one gripping device to penetrate or create an indentation in
the borehole wall (or casing if the borehole wall is cased). In
some embodiments, the at least one gripping device has at least one
protruding spike, which may be three protruding spikes arranged in
a triangular geometry relative to one another. In some embodiments,
the sufficient force is applied by extendible mechanical arms, an
inflatable bladder, bow springs, a clamping device, a locking
device, or combinations thereof.
[0006] The identified embodiments are exemplary only and are
therefore non-limiting. The details of one or more non-limiting
embodiments of the present disclosure are set forth in the
accompanying drawings and the descriptions below. Other embodiments
should be apparent to those of ordinary skill in the art after
consideration of the present disclosure.
DESCRIPTION OF THE DRAWINGS
[0007] Certain embodiments of the present disclosure will hereafter
be described with reference to the accompanying drawings, wherein
like reference numerals denote like elements. It should be
understood, however, that the accompanying drawings illustrate only
the various implementations described herein and are not meant to
limit the scope of various technologies described herein. The
drawings are as follows:
[0008] FIG. 1 is a schematic illustration of a vertical seismic
profiling ("VSP") operation suitable for use with embodiments of
devices and methods of the present disclosure.
[0009] FIG. 2 is a schematic illustration of a well logging data
acquisition and logging system suitable for use with embodiments of
devices and methods of the present disclosure.
[0010] FIGS. 3a, 3b, 3c, and 3d are schematic representations of
several VSP survey configurations.
[0011] FIG. 4 is a schematic illustration of an embodiment of a
sensor module in accordance with an embodiment of the present
disclosure in contact with a borehole wall, shown in perspective
partial plan view.
DETAILED DESCRIPTION
[0012] Illustrative embodiments and aspects are described below. It
will be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions can be made
to achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such development effort might be complex and
time-consuming, but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of the
present disclosure.
[0013] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as is commonly understood by one
of ordinary skill in the art to which the present disclosure
belongs. In the event that there is a plurality of definitions for
a term herein, those in this section prevail unless stated
otherwise.
[0014] Wherever the phrases "for example," "such as," "including"
and the like are used herein, the phrase "and without limitation"
is understood to follow unless explicitly stated otherwise.
[0015] The terms "comprising" and "including" and "involving" (and
similarly "comprises" and "includes" and "involves") are used
interchangeably and mean the same thing. Specifically, each of the
terms is defined consistent with the common United States patent
law definition of "comprising" and is therefore interpreted to be
an open term meaning "at least the following" and is also
interpreted not to exclude additional features, limitations,
aspects, etc.
[0016] The term "about" is meant to account for variations due to
experimental error. All measurements or numbers are implicitly
understood to be modified by the word about, even if the
measurement or number is not explicitly modified by the word
about.
[0017] The term "substantially" (or alternatively "effectively") is
meant to permit deviations from descriptor that don't negatively
impact the intended purpose. Descriptive terms are implicitly
understood to be modified by the word substantially, even if the
term is not explicitly modified by the word substantially.
[0018] The terms "wellbore" and "borehole" are used
interchangeably.
[0019] "Measurement While Drilling" ("MWD") can refer to devices
for measuring downhole conditions including the movement and
location of the drilling assembly contemporaneously with the
drilling of the well. "Logging While Drilling" ("LWD") can refer to
devices concentrating more on the measurement of formation
parameters. While distinctions may exist between these terms, they
are also often used interchangeably. For purposes of the present
disclosure MWD and LWD are used interchangeably and have the same
meaning. That is, both terms are understood as related to the
collection of downhole information generally, to include, for
example, both the collection of information relating to the
movement and position of the drilling assembly and the collection
of formation parameters.
[0020] A "downhole tool" can be any instrumentation used in a
borehole such as a bare sensor, or a sensor deployed on a shuttle,
or a sensor deployed on a MWD drill string.
[0021] A vertical seismic acquisition in a borehole is illustrated
in FIG. 1. A cable 21 carrying a plurality of VSP shuttles 211 is
suspended from the surface 201 of a borehole 20 into the borehole
20. System noise is alleviated or avoided by pushing or wedging the
shuttles against the formation 202 or any casing surrounding the
wellbore 20 using any means known in the art, including inflatable
bellows, or as shown, a clamping or locking mechanism 212.
[0022] The clamping or locking mechanism 212 can be based on the
use of springs, telescopic rams or pivoting arms as shown. The
shuttles 211 can carry transducer elements 213 to measure the
velocity or acceleration in one of three independent directions.
The clamping mechanism 212 couples the transducers 213 to the
borehole wall. In a VSP operation, a significant decrease in the
signal-to-noise ratio can be observed when the geophone loses
contact with the wall of the borehole 20.
[0023] On the surface, a cable reel 214 and feed 215 supports the
cable 21. Measurement signals or data are transmitted through the
cable 21 to a base station 22 on the surface for further
processing. The cable can be an armored cable as used for wireline
operations.
[0024] In operation a source 203 as shown is activated generating
seismic waves which travel through the formation 202. Where there
are changes in formation impedance (as indicated by dashed lines
204), part of the seismic energy may be reflected and/or refracted.
The transducers 213 register movements of the earth and the
measurements are transmitted directly or after in-line digitization
and/or signal processing to the surface base station 22 for
storage, transmission and/or further processing. The subsequent
data processing steps are known and well established in the field
of hydrocarbon exploration and production.
[0025] FIG. 2 illustrates another embodiment of a wellsite system
in which the present disclosure can be employed. Here again, the
wellsite can be onshore or offshore. In this exemplary system, a
borehole 11 is formed in subsurface formations by rotary drilling
in a manner that is well known. Various embodiments can also use
directional drilling.
[0026] A drill string 12 is suspended within the borehole 11 and
has a bottom hole assembly 100 which includes a drill bit 105 at
its lower end. The surface system includes platform and derrick
assembly 10 positioned over the borehole 11, the assembly 10
including a rotary table 16, kelly 17, hook 18 and rotary swivel
19. The drill string 12 is rotated by the rotary table 16,
energized by means not shown, which engages the kelly 17 at the
upper end of the drill string. The drill string 12 is suspended
from a hook 18, attached to a traveling block (also not shown),
through the kelly 17 and a rotary swivel 19 which permits rotation
of the drill string relative to the hook. As is well known, a top
drive system could alternatively be used.
[0027] In the example of this embodiment, the surface system
further includes drilling fluid or mud 26 stored in a pit 27 formed
at the well site. A pump 29 delivers the drilling fluid 26 to the
interior of the drill string 12 via a port in the swivel 19,
causing the drilling fluid to flow downwardly through the drill
string 12 as indicated by the directional arrow 8. The drilling
fluid exits the drill string 12 via ports in the drill bit 105, and
then circulates upwardly through the annulus region between the
outside of the drill string and the wall of the borehole, as
indicated by the directional arrows 9. In this well known manner,
the drilling fluid lubricates the drill bit 105 and carries
formation cuttings up to the surface as it is returned to the pit
27 for recirculation.
[0028] The bottom hole assembly 100 of the illustrated embodiment
includes a logging-while-drilling (LWD) module 120, a
measuring-while-drilling (MWD) module 130, a roto-steerable system
and motor 150, and drill bit 105.
[0029] The LWD module 120 can be housed in a drill collar, as is
known in the art, and may contain one or more logging tools. It
will also be understood that more than one LWD and/or MWD module
can be employed, e.g. as represented at 120A. (References,
throughout, to a module at the position of 120 can alternatively
mean a module at the position of 120A as well.) The LWD module
includes capabilities for measuring, processing, and storing
information, as well as for communicating with the surface
equipment. In some embodiments, the LWD module includes a seismic
measuring device.
[0030] The MWD module 130 can also be housed in a drill collar, as
is known in the art, and may contain one or more devices for
measuring characteristics of the drill string and drill bit. For
example, the MWD module may include one or more of the following
types of measuring devices: a weight-on-bit measuring device, a
torque measuring device, a vibration measuring device, a shock
measuring device, a stick slip measuring device, a direction
measuring device, and an inclination measuring device. The MWD tool
can further include an apparatus (not shown) for generating
electrical power to the downhole system. This may include a mud
turbine generator powered by the flow of the drilling fluid, it
being understood that other power and/or battery systems may be
employed.
[0031] Borehole seismic surveys are versatile downhole measurement
techniques used in the oil field. The various types of waves
generated and survey geometries achieved combine to deliver
information relating to subsurface structural features such as for
example reservoir depth, extent, heterogeneity as well as about
hydrocarbon content, rock mechanical properties, pore pressure,
enhanced-oil-recovery progress, elastic anisotropy,
natural-fracture orientation and density, and induced-fracture
geometry. Borehole seismic surveys, or VSPs, reduce the uncertainty
of reservoir properties near the borehole. With their measurement
scale between those of well logs and surface seismic surveys, VSPs
extend near-wellbore observations, explore interwell volumes, and
link time-based surface seismic images with depth-based logs.
[0032] FIG. 3 illustrates several VSP survey configurations. The
VSP surveys enable interrogation of the earth to obtain among other
things: (i) a detailed velocity profile at the seismic scale which
can be correlated to depth (log) and time (seismic) as well as (ii)
some type of fracture image (e.g. walkaway, etc.).
[0033] FIG. 3 also illustrates a seismic-while-drilling tool which
can be the LWD tool 120, or can be part of an LWD tool suite 120A
of the type disclosed in P. Breton et al., "Well Positioned Seismic
Measurements," Oilfield Review, pp. 32-45, Spring, 2002. The
downhole LWD tool can have a single receiver (as depicted in FIGS.
3A and 3B), or plural receivers (as depicted in FIGS. 3C and 3D),
and can be employed in conjunction with a single seismic source at
the surface (as depicted in FIGS. 3A and 3C) or plural seismic
sources at the surface (as depicted in FIGS. 3B and 3D).
Accordingly, FIG. 3A, which includes reflection off a bed boundary,
and is called a "zero-offset" vertical seismic profile arrangement,
uses a single source and a single receiver, FIG. 3B, which includes
reflections off a bed boundary, and is called a "walkaway" vertical
seismic profile arrangement, uses plural sources and a single
receiver, FIG. 3C, which includes refraction through salt dome
boundaries, and is called a "salt proximity" vertical seismic
profile, uses a single source and plural receivers, and FIG. 3D,
which includes some reflections off a bed boundary, and is called a
"walk above" vertical seismic profile, uses plural sources and
plural receivers.
[0034] As mentioned, a significant decrease in signal-to-noise
ratio can be observed when the geophone loses contact with the wall
of the borehole. Referring now to FIG. 4, the downhole tool 300,
according to the present disclosure, which may be a bare sensor, a
shuttle having one or more sensors, or a MWD (or LWD) tool having
one or more sensors, can cooperate with suitable means for
maintaining contact between the sensor and borehole to reduce or
eliminate loss of contact. More specifically, the downhole tool 300
includes gripping devices 310 capable of puncturing, or creating an
indentation in, the borehole wall 315 (or the casing of a borehole
wall, if the borehole wall is cased) when appropriate force is
applied to the downhole tool 300. The sensors may be any downhole
sensor for which contact between the sensor and borehole wall is
desirable, for example geophones or accelerometers.
[0035] As shown, the downhole tool 300 is a shuttle having a
housing 305 to which three gripping devices 310 are mounted. Also
as shown, the gripping devices 310 are spikes configured in a
triangular geometry relative to one another. Embodiments within
scope of the present disclosure are not limited to this specific
embodiment (i.e. three spikes in a triangular configuration about
the downhole tool housing), however, such a configuration may
provide additional stabilization as compared to, as examples, a
single spike (or single protrusion or gripping device) or as
compared to a linear arrangement. As a person of skill can
understand from reading the present disclosure any gripping device
and any configuration of gripping device which reduces the chance
of slippage as compared to conventional devices which rely merely
on friction between the surface of the downhole tool and borehole
wall (or casing) are within scope of the present disclosure.
[0036] The shuttle housing 305 and gripping devices 310 can be a
unitary device, or the gripping devices 310 can be mounted onto the
housing 305, as shown in FIG. 4. As a person of skill would
understand from reading the present disclosure, the gripping
devices 310 can be made of any material that is able to withstand
the force applied to the housing 305, for causing and/or
maintaining contact between the sensor module (or downhole tool)
and the borehole wall, and the material should be desirably harder
than the borehole wall (or casing of the borehole wall). One
example of a suitable material is tungsten carbide. However a
person of skill with an understanding from the present disclosure
can select suitable alternative materials such as high speed steel
and ceramics.
[0037] In operation, the downhole tool 300 is lowered into a
borehole, and force is applied to the downhole tool 300 to cause it
to contact and/or maintain contact with the borehole wall in order
to couple the sensor to the formation. The force can applied by any
suitable means, such as the clamping or locking mechanism 212 shown
in FIG. 1. Alternatively, or in addition, the force may be applied,
for example, by inflatable bellows, extendible mechanical arms, or
bow springs. The force should be sufficient to also cause the
gripping devices 310 to puncture, or create an indentation in, the
borehole wall (or the casing of a borehole wall, if the borehole
wall is cased). As a result, because at least a portion of the
gripping devices 310 reside below the original surface of the
borehole wall 320, the downhole tool 300 resists slipping and loss
of contact with the borehole wall to a greater degree than a
downhole tool without the gripping devices 310.
[0038] In some embodiments, the disclosed contact arrangement
between downhole tool and borehole wall and method of maintaining
contact between the downhole tool and borehole wall may enhance
coupling between the sensor and formation, which is now not limited
to frictional contact for reducing slippage between the sensor and
the formation surface. Further, in some embodiments, the resultant
coupling frequency is generally higher than similar non-penetrative
systems. For example, in some embodiments, a downhole tool with
gripping devices according to the present disclosure (such as the
exemplified spikes arranged in a triangular geometry) has a
coupling frequency of at least 1000 Hz as compared to the few
hundred Hz of conventional systems without the gripping devices.
Consequently, in some embodiments, downhole tools equipped with
gripping devices should result in improved data collection as
compared to downhole tools without gripping devices in view of the
fact that microseismic events can contain high frequency
components, for example at least up to 2000 Hz. Accordingly, some
embodiments according to the present disclosure may improve
coupling between the sensor package and the formation surface to be
monitored. And some and/or further embodiments according to the
present disclosure may enhance the frequency range due to higher
coupling frequency as compared to downhole tools without the
gripping devices.
[0039] While the detailed description has been made with respect to
a limited number of embodiments, those skilled in the art, having
the benefit of the present disclosure, will appreciate numerous
modifications and variations therefrom. For example, while the
specification refers mainly to seismic monitoring, the devices and
methods are also applicable to any sensor system which could
benefit from contact between the sensor and borehole wall or
surface to be monitored. It is intended that the appended claims
cover such modifications and variations as fall within the true
spirit and scope of the present disclosure.
* * * * *